Method of manufacturing blade-rings for steam and gas turbines.



A F. LJUNGS-TRUM. METHOD OF MANUFACTURING BLADE RINGS FOR STEAM AND GASTURBINES.

APPLICATION FILED JAN.31, 1913.

Patented June 30,1914.

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Specification of Letters Patent.

Patented June 3(1 191%.

Application filed January 31, 19191 Serial No. i 4=5,4*1'?.

of Manufacturing Blade-Rings for Steam and Gas Turbines, of which thefollowing is a specification.

In manufacturing blade rings for steam or gas turbines especially forradial turbines it is of great importance that the blades being attachedat both ends to reinforcing rings are secured accurately in such mannerthat firstly the distance between the blades and secondly their outletangle is properly determined. i

In the methods to which the blades are now employedaccording guided atboth ends there arise many difficulties and disad-- the blades aresecured by autogenous welding, because a high heating must be used justat those points, z". e. the ends where the blades are .guided. Suchheating causes a comparatively great deformation, not only the angleposition of the blades being varied but even blades being bent and thedistance between the same bein varied.

The present invention relates to a method adapted to avoid the saiddisadvantages. Further the invention has for its object to provide aguide for the blades between the ends of the same, whereby not only abending of the blades during the securing is prevented but also thespecial guide at theends can be dispensed with.

The method consists in rigidly combining the blades at their ends, byspecial devices during the securing, placement of the blades isprevented at the securing process; The said devices preferably consistof annular rings or the like through which the blades pass and which areinserted at one or more places between the ends of the blades, the ringsbeing provided with holes, which are shaped so as to guide or supportthe blades in such a way that the blades will be prevented from turningor moving in relation to each other. Thus a displacement of the bladesis prevented during the welding of the ends thereof.

An embodiment of the invention is shownin the accompanying drawing.

so that a relative dis- Figures 1 and 2 show a part of a blade ringinside elevation and in plan respec: tively. Fig. 3 shows a part of aguiding ring. Figs. 4 and- 5 show different forms of the holes in thesupporting rings. Fig. 6 represents a front elevation of theunderlapping. end 0' of one of the rings 0; Fig. 7 represents a similarview of the overlapping end of said ring; and Fig. 8 represents asimilar view of these ends with the latter superposed on the former asin use, the finder-lapping end being shaded for distincron.arindicatesthe reinforcing rings and 1) indicates the blades which: passthrough the guiding or supporting rings a of sheet iron or othersuitable material. In the drawing only two such rings are shown. Thenumber of rings canhowever be varied. The guiding or supporting ringscan be formed as integral rings or consist of a plurality of "ring partsor sections,- the ends of which preferably overlap each other.

The holes 03 in the supporting rings can be shaped in conformity to thecross sections of the blades, as shown in Fig. 3. As it is verydifficult, however, to stamp the thin points of the holes and as acorrespondingly formed stamp, further, will not be strong enough, theholes are preferably shaped as shown in Figs. 1 and 5 that is to say insuch a way that the edges of the holes abut against the points of theblades only at the one side of these latter. The holes can be madegreater than the crosssections of the blades, two rings being placedlaterally of each other in such a manner that the holes are set somewhatout of line with each other. The blades then abut with the one sideagainst the edge ofa hole in the one ring, while the blades with theirother side abut against the edge'of 2. corresponding hole in the otherring. Figs. 6, 7 and 8 illustrate the end of the rings thus constructedand applied, having holes of different forms, chosen by way of example.The unde'rlapping end 0 of the ring (Figs. 6 and 8) has a hole all? ofcurvilinear border onone side, the other three borders being straightsides of a quadrilateral. The overlapping end 0 of said ring (Figs. 7and 8) has a hole 01' with the curved border on the other side, thecurvature being out-ward instead of inward and greater than the inwardcurvature before mentioned. en

the end a is laid upon the end 0, as shown in Fig. 8, the degree ofoverlapping may be so regulated as to leave uncovered only the left partof opening d and the overlapping right part of openingd these two partscombining in one opening, approximately of crescent form, through bothplates.

It will be clear that, if the rings consist of ring sections, the endsthereof may not necessarily overlap each other as shown in Figs. 1- and2, but they may abut against each other. After the blade rings have beenproperly arranged the supporting rings are eliminated for instance bymaking a cut at each blade through the inner anc outer edge of thesupporting ring, or by employing supporting rings of an easily fusiblemetal which can be removed by melting.

I am aware that it is not broadly new to hold metallic parts in a clamp,to be brazed or welded and do not claim the same. I am also aware moreparticularly that this process or method of thus holding duri suchwelding or brazing has been appli e to the manufacture of reamers ormilling tools and my claims are not intended to cover, and do not coverthe same. But

Having now described my invention, what I claim and.desire to protect byLetters Patent is:

l. The process of manufacturing blade rings for steam turbinesconsisting in the.

following steps, first rigidly connecting the blades together near theirends by suitable parts adapted to hold a series of said blades in properparallel position and prevent their relative displacement, secondlyfitting said ends into holes in reinforcing rings thirdly welding saidends to said rings and finally removing said parts which have previouslyheld said ends together.

2. The process of manufacturing blade rings for turbines consisting inthe following steps; first, rigidly connecting the blades together bytemporary supporting rings adapted to hold them in proper positionparallel to each other but to be easily cut away; secondly, fitting theends of said blades into the permanent reinforcing rings; and finallycutting away said temporary supporting rings. 7

In testimony whereof I have affixed my signature in presence of twowitnesses.

FREDRIK LJUNGSTROM. Witnesses:

FREDRIK GANNAR Bonn,v INETA PRIoU.

